Method for stabilizing bubbles within a cavitation chamber

ABSTRACT

A method for achieving bubble stability within a cavitation chamber is provided. At least one impeller is located within the cavitation chamber. By rotating the impeller, bubbles within the cavitation chamber are stabilized at a location near, or along, the impeller&#39;s axis of rotation. Preferably the axis of rotation is positioned in a substantially horizontal plane, thus allowing the rotating impeller to counteract the tendency of the bubbles to drift upward and to accumulate on the upper, inner surfaces of the cavitation chamber. The impeller can be rotated continuously throughout the cavitation process or stopped prior to cavitating the bubbles within the cavitation chamber. In the latter scenario, the impeller can be stopped, and if desired locked, at a specific rotational position, thus minimizing possible interference between the impeller and the source of the cavitation energy.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.11/038,344, filed Jan. 18, 2005, the disclosure of which is incorporatedherein by reference for any and all purposes.

FIELD OF THE INVENTION

The present invention relates generally to cavitation systems and, moreparticularly, to a method for stabilizing bubbles within a cavitationchamber via fluid rotation.

BACKGROUND OF THE INVENTION

Sonoluminescence is a well-known phenomena discovered in the 1930's inwhich light is generated when a liquid is cavitated. Although a varietyof techniques for cavitating the liquid are known (e.g., sparkdischarge, laser pulse, flowing the liquid through a Venturi tube), oneof the most common techniques is through the application of highintensity sound waves.

In essence, the cavitation process consists of three stages; bubbleformation, growth and subsequent collapse. The bubble or bubblescavitated during this process absorb the applied energy, for examplesound energy, and then release the energy in the form of light emissionduring an extremely brief period of time. The intensity of the generatedlight depends on a variety of factors including the physical propertiesof the liquid (e.g., density, surface tension, vapor pressure, chemicalstructure, temperature, hydrostatic pressure, etc.) and the appliedenergy (e.g., sound wave amplitude, sound wave frequency, etc.).

Although it is generally recognized that during the collapse of acavitating bubble extremely high temperature plasmas are developed,leading to the observed sonoluminescence effect, many aspects of thephenomena have not yet been characterized. As such, the phenomena is atthe heart of a considerable amount of research as scientists attempt tofurther characterize the phenomena (e.g., effects of pressure on thecavitating medium) as well as its many applications (e.g.,sonochemistry, chemical detoxification, ultrasonic cleaning, etc.).By-products of this research have been several patents claiming variousaspects of the process. One such patent, U.S. Pat. No. 4,333,796,discloses a cavitation chamber that is generally cylindrical althoughthe inventors note that other shapes, such as spherical, can also beused. It is further disclosed that the chamber is comprised of arefractory metal such as tungsten, titanium, molybdenum, rhenium or somealloy thereof. U.S. Pat. No. 4,333,796 states that the temperaturesachieved by a collapsing bubble depend strongly on whether or not theinterface of the bubble and the host liquid remain spherical duringcollapse. Noting that the earth's gravitational field is an asymmetricforce that can cause bubble deformation, the patent discloses that apreferred cavitation chamber includes means for applying a magneticfield to cancel the gravitational force, thus creating a zero-gravityfield within the cavitation zone. U.S. Pat. No. 4,333,796 furtherdiscloses that if the bubble is cylindrical or quasi-cylindrical, smallsurface perturbations will neither grow nor decay. The patent disclosesseveral means of achieving such a bubble shape, including imposing atime-varying magnetic field. U.S. Pat. No. 4,563,341, acontinuation-in-part of U.S. Pat. No. 4,333,796, discloses the use of avertical standing pressure wave excited by a transducer in the bottomwall of the chamber as a means of reducing the effects of the earth'sgravitational field within the cavitation zone.

U.S. Pat. No. 5,659,173 discloses a sonoluminescence system that uses atransparent spherical flask. The spherical flask is not described indetail, although the specification discloses that flasks of Pyrex®,Kontes®, and glass were used with sizes ranging from 10 milliliters to 5liters. U.S. Pat. No. 5,659,173 does not disclose any means forstabilizing bubbles within the cavitation zone.

U.S. Pat. No. 5,858,104 discloses a shock wave chamber partially filledwith a liquid. The remaining portion of the chamber is filled with gaswhich can be pressurized by a connected pressure source. Acoustictransducers mounted in the sidewalls of the chamber are used to positionan object within the chamber. Another transducer mounted in the chamberwall delivers a compressional acoustic shock wave into the liquid. Aflexible membrane separating the liquid from the gas reflects thecompressional shock wave as a dilatation wave focused on the location ofthe object about which a bubble is formed.

PCT WO 03/077260 discloses a nuclear fusion reactor in which a bubble offusionable material is compressed using an acoustic pulse, thecompression of the bubble providing the necessary energy to inducenuclear fusion. The nuclear fusion reactor is spherically shaped andfilled with a liquid such as molten lithium or molten sodium. To formthe desired acoustic pulse, a pneumatic-mechanical system is used inwhich a plurality of pistons associated with a plurality of air gunsstrike the outer surface of the reactor with sufficient force to form ashock wave within the reactor's liquid. The application disclosesreleasing the bubble at the bottom of the chamber and applying theacoustic pulse as the bubble passes through the center of the reactor. Anumber of methods of determining when the bubble is approximatelylocated at the center of the reactor are disclosed. The application alsodiscloses that a bubble positioning system may be used, the systemcomprised of two pairs of jets which flow the liquid within the reactorinwardly, thereby directing the bubble towards the center of the vessel.

PCT WO 96/21230 discloses a non-periodically forced bubble fusionapparatus. The apparatus is comprised of a liquid-filled pressure vesselinto which deuterium gas bubbles are injected. A non-periodic pressurefield is generated within the liquid, the pressure field causing thebubbles to oscillate and become compressed thereby heating the bubblesto a temperature which is sufficiently high to cause a fusion reactionin the hot deuterium plasma formed at implosion stagnation. Theapplication does not disclose any means of stabilizing the movement ofthe injected bubbles or positioning the bubbles within the pressurevessel.

In a paper entitled Sonoluminescence and Bubble Dynamics for a Single,Stable, Cavitation Bubble (J. Acoust. Soc. Am. 91 (6), June 1992),Felipe Gaitan et al. modeled the motion of acoustically driven bubblesbased on the results of their single bubble experiments. The authors'experimental apparatus included a liquid filled levitation cell in whicha stationary acoustic wave was excited, the stationary wavecounteracting the hydrostatic or buoyancy force, thus stabilizing abubble injected into the cell and allowing it to remain suspended in theliquid indefinitely.

Avik Chakravarty et al., in a paper entitled Stable SonoluminescenceWithin a Water Hammer Tube (Phys Rev E 69 (066317), Jun. 24, 2004),investigated the sonoluminescence effect using a water hammer tuberather than an acoustic resonator, thus allowing bubbles of greater sizeto be studied. The experimental apparatus employed by the authorsincluded a sealed water hammer tube partially filled with the liquidunder investigation. The water hammer tube was mounted vertically to theshaft of a moving coil vibrator. Cavitation was monitored both with amicrophone and a photomultiplier tube. To stabilize the bubbles withinthe water hammer tube and minimize the effects of the tube walls, in oneembodiment the tube was rotated about its axis.

Although a variety of sonoluminescence systems have been designed,typically these systems suffer from a variety of shortcomings due to theinherent instability of the cavitating bubbles. The present inventionovercomes these shortcomings by providing a method for stabilizing thecavitating bubbles within the cavitation chamber.

SUMMARY OF THE INVENTION

The present invention provides a method for achieving bubble stabilitywithin a cavitation chamber. At least one impeller is located within thecavitation chamber. By rotating the impeller, bubbles within thecavitation chamber are stabilized at a location near, or along, theimpeller's axis of rotation. In at least one embodiment the axis ofrotation is positioned in a substantially horizontal plane, thusallowing the rotating impeller to counteract the tendency of the bubblesto drift upward and to accumulate on the upper, inner surfaces of thecavitation chamber.

In at least one embodiment of the invention the impeller is rotatedcontinuously throughout the cavitation process. Alternately, impellerrotation can be stopped prior to cavitating the bubbles within thecavitation chamber. In this instance the impeller can be stopped, and ifdesired locked, at a specific rotational position, thus minimizingpossible interference between the impeller and the source of thecavitation energy.

A further understanding of the nature and advantages of the presentinvention may be realized by reference to the remaining portions of thespecification and the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a conceptual illustration of the principal elements of theinvention implemented in an exemplary embodiment;

FIG. 2 illustrates the effects of cavitation fluid rotation on aplurality of bubbles contained within a cavitation chamber;

FIG. 3 illustrates a specific bubble geometry with a few small bubbleswithin a cylindrical impeller;

FIG. 4 illustrates a relatively large number of bubbles within acylindrical cavity prior to bubble collapse;

FIG. 5 illustrates the bubbles of FIG. 4 during bubble collapse;

FIG. 6 illustrates one, extremely large cylindrical bubble within acylindrical cavity prior to bubble collapse;

FIG. 7 illustrates the degeneration of the cylindrical bubble of FIG. 6during bubble collapse;

FIG. 8 is a cross-sectional view of a preferred impeller design for usewith a cylindrical cavitation chamber;

FIG. 9 is a perspective view of the impeller shown in FIG. 8;

FIG. 10 is a perspective view of the external body portion of acavitation chamber for use with the impeller shown in FIG. 8;

FIG. 11 is a cross-sectional view of the chamber shown in FIG. 10;

FIG. 12 is a perspective view of a cylindrical bladeless impeller;

FIG. 13 is a cross-sectional view of another embodiment of the inventionin which the cylindrical cavity of FIG. 11 is replaced with a sphericalcavity;

FIG. 14 is an illustration of a spherical cavity that cannot bedisassembled;

FIG. 15 is a side view of a single-bladed impeller for use with thespherical cavitation chamber of FIG. 14;

FIG. 16 is a top view of the single-bladed impeller of FIG. 15;

FIG. 17 is a cross-sectional view of the spherical cavity of FIG. 14with the impeller assembly of FIG. 15 installed; and

FIG. 18 is a cross-sectional view of a spherical cavity similar to thatshown in FIG. 14 with a pair of impeller assemblies similar to theassembly shown in FIGS. 15 and 16.

DESCRIPTION OF THE SPECIFIC EMBODIMENTS

FIG. 1 is a conceptual illustration of the principal elements of theinvention implemented in an exemplary embodiment. More specifically, theinvention is fitted within a sonoluminescence cavitation chamber 101,hereafter referred to as simply a cavitation chamber. The invention usesat least one impeller 103, and in at least one embodiment a pair ofimpellers 103/104, to stabilize and axially center bubbles within thecavitation chamber. If a pair of impellers is used, preferably the axesof the two impellers are coaxial as shown. Each impeller shaft isattached to a motor 105 and a motor controller 107. It will beappreciated that in the description that follows unless a specificembodiment is being discussed with a particular impeller arrangement,the general description refers to both single impeller and multipleimpeller embodiments.

Impeller 103, alternately impellers 103/104, serve many purposes. First,the impeller(s) helps to keep the cavitating bubbles away from the innerchamber surfaces. Second, the impeller(s) centers the bubble or bubblesalong the impeller's axis. Therefore if the impeller axis is maintainedin a horizontal plane, as preferred, the impeller's rotation can be usedto overcome the bubble's tendency to drift upward through the chamber.This benefit is especially important if larger bubbles are used in thecavitation process. Third, by locating the bubbles in a known positionthrough the use of the impeller(s), the means used to drive energy intothe cavitation chamber can be designed to more efficiently couple thedriving energy into the cavitating bubble. Fourth, the impeller(s) canbe used to improve the sphericity of the bubbles during the cavitationprocess, in particular during the period of cavitation in which thebubbles are collapsing. As a result, smaller bubble diameters can beachieved prior to bubble deformation or disintegration.

It will be appreciated that the present invention, i.e., a means ofrotating the cavitation fluid within a cavitation chamber, is notlimited to a particular outside chamber diameter, inside chamberdiameter, chamber material or chamber shape (e.g., cylindrical chambers,spherical chambers, rectangular chambers, etc.). Such information, asprovided herein, is only meant to provide exemplary chamberconfigurations for which the present invention is applicable. Similarly,the invention is not limited to the acoustic drivers 109 shown in FIG.1, rather the invention can be used with any of a variety of cavitationdriver types, numbers or mounting locations. Similarly, the invention isnot limited to a specific system configuration, i.e., the invention canbe used with a sealed chamber or a chamber in which the cavitation fluidpasses through a circulatory system as shown in FIG. 1. If a circulatorysystem is used, it may or may not include a degassing system 111, and/ora bubble trap 113, and/or a filter 115 and/or a heat exchange system117. If a circulatory system is used, the chamber inlet and outletlocations as well as the selected cavitation fluid flow rate arepreferably designed to minimize disruption of cavitation fluid rotation.Typically the cavitation fluid is degassed (e.g., of air) prior toinitiating cavitation, and typically before initiating impellerrotation.

FIG. 2 illustrates some of the primary shapes associated with bubblerotation. Initially, immediately after the impeller(s) starts to rotateand assuming a relatively low impeller rotation velocity, bubbles 201are drawn toward the rotational axis 203. During this stage of rotationand with low rotation velocities, the bubbles remain roughly sphericalin shape as the force exerted by the rotating fluid is insufficient toovercome the bubbles' tendency to assume a spherical shape, therebyminimizing the bubble's surface tension. As the rotational velocityincreases, the bubbles 205 are drawn more forcefully towards therotational axis 203. Simultaneously, bubbles 205 begin to elongate asillustrated. At this stage typically there is a ‘string’ of bubblesformed along the rotational axis, the sphericity of each of the bubblesdepending strongly on the rotational velocity of the fluid. If thebubbles are sufficiently large, or the rotational velocity sufficientlyhigh, often multiple bubbles will coalesce into larger, elongatedbubbles 207, the number and size of bubbles 207 depending upon thenumber of bubbles, their sizes, and the rotational velocity. Whether thebubbles are vapor filled (evacuated) or gas filled, their behavior issubstantially the same. Of course other factors such as fluid pressureand composition also determine the sphericity of the bubbles for a givenrotational velocity.

As previously noted, the degree to which the bubble(s) is centered alongthe fluid's axis of rotation as well as the degree to which thebubble(s) is elongated depends on the fluid rotation velocity and thelength of time that the fluid has been rotated. Additionally impellerrotation can either be continuous or non-continuous. The inventor hasfound that continuous impeller rotation is best employed when thedrivers are comprised of acoustic drivers, and non-continuous impellerrotation is best when it is desirable to place (and if desired, lock)the impeller blades at a specific location prior to initiatingcavitation implosions. It will be appreciated that other factors, suchas the desired bubble shape or location, can also influence whetherimpeller rotation should be continuous or non-continuous.

The inventor has found that depending upon bubble density (i.e., number)and bubble size (i.e., bubble volume), impeller rotation can be used togenerate a variety of different bubble geometries. FIGS. 3-7 illustratethree such geometries. For purposes of illustration, these bubblegeometries are shown within a cylindrical impeller 300 comprised of apair of impeller blades 301, the impeller axis of rotation 303 locatedin a horizontal plane. FIG. 3 illustrates a few (e.g., three) smallbubbles 305 held along axis 303. FIGS. 4 and 5 illustrate a large numberof relatively large volume bubbles 401 before (i.e., FIG. 4) and during(i.e., FIG. 5) bubble collapse. FIG. 6 illustrates one, extremely largecylindrical bubble 601 prior to collapse. During collapse (i.e., FIG.7), bubble 601 degenerates into a plurality of small bubbles 701.

As previously noted, a variety of different bubble geometries can beachieved by varying the impeller rotation velocity, selecting eithercontinuous or non-continuous impeller rotation, and controlling thebubble density and bubble volume. Additionally it will be appreciatedthat other parameters such as impeller design and cavitation fluidcomposition affect the bubble geometry. With respect to composition, thetwo primary attributes of the selected cavitation medium which controlthe response of a bubble to the rotating impeller(s) is the medium'sviscosity and surface tension. Increasing the viscosity of thecavitation medium affects the ease by which the impeller(s) can rotatewithin the fluid as well as the rate at which bubbles can move withinthe fluid, both during impeller rotation and after cessation of impellerrotation. The surface tension affects how quickly a bubble undergoeselongation in response to impeller rotation.

Although as previously noted the invention is not limited to a specificdesign for either the impeller(s) or the chamber, a preferred embodimentof the invention for use with a cylindrical chamber is shown in FIGS.8-10. As shown in the cross-sectional view of FIG. 8 and the perspectiveview of FIG. 9, impeller 800 has a pair of impeller blades 801. Notethat in FIG. 9, impeller 800 has been rotated to provide a clearer viewof impeller blades 801. For applications in which stable on-axis bubblesare desired, preferably the outside diameter of impeller 800 is smallerthan the inside diameter of the cavitation chamber by a sufficientamount to minimize wall turbulence that can be caused by rotating theimpeller blades in near proximity to the cavity wall. For applicationsin which bubble clouds are desired, preferably impeller 800 utilizesthick impeller blades and the outside diameter of the impeller is onlyslightly smaller than the inside of the cavitation chamber, therebymaximizing wall turbulence.

For ease of fabrication, impeller 300 is fabricated from a cylinder. Inone exemplary embodiment the cylinder is 7 inches long with an outsidediameter of 2.5 inches and a wall thickness of 0.0625 inches. Preferablyimpeller 800 is fabricated from a metal such as stainless steel. Duringimpeller fabrication, most of the wall of the cylinder is machined away,leaving only blades 801 and a portion 803 of the cylinder at either end.Cylinder end caps 805 and 806 are attached to end portions 803 using anyof a variety of means, including but not limited to press-fitting,bonding, brazing or bolting the pieces together. As shown in furtherdetail below, end cap 806 includes a spindle 807 which confines the axisof rotation of the impeller along the centerline of the chamber. End cap805 includes a drive shaft 809, the drive shaft providing a means forcoupling impeller 800 to a motor (not shown). Although the inventiondoes not require that impeller 800 use two blades 801 as shown, theinventor has found that two blades provide sufficient fluid rotationcapabilities while also providing a strong mechanical design. Otherimpeller configurations, however, are clearly envisioned (e.g., threeblades, four blades, etc.). The primary requirements placed on thenumber and locations of the impeller blades are (i) balanced and stableoperation during rotation and (ii) minimization of impeller createdturbulence.

FIG. 10 is a perspective view of the external body portion of acavitation chamber 1000 for use with impeller 800. To simplifyfabrication, chamber 1000 is fabricated from a single piece of material1001, preferably stainless steel. A cylindrical hole 1003 is bored intoblock 1001 such that impeller 800 fits within the hole as shown in thechamber cross-sectional view of FIG. 11. Assuming an impeller with anoutside diameter of 2.5 inches, preferably the inside diameter of thecavitation cavity (i.e., hole 1003) is 3.0 inches. Although hole 1003need not be bored completely through block 1001 as shown, the inventorhas found that chamber assembly and maintenance is simplified by doingso. Accordingly the preferred embodiment of the invention uses a pair ofend caps 1103/1105 to seal chamber 1000, the end caps preferably boltedto block 1001 with a plurality of bolts 1107 and sealed with one or moresealing members 1109 (e.g., o-rings). End cap 1103 includes one or morebearings 1111 to insure proper rotation of impeller spindle 1107, andthus impeller 800. End cap 1105 preferably includes at least one bearing1113 and multiple seals 1115. A secondary end cap 1117 with sealingmembers 1119 (e.g., o-rings) may be used, as shown, to hold seals 1115and bearings 1113 in place and to provide additional sealing of thechamber. Preferably multiple Teflon o-rings 1121 are inset into both endcaps 1103/1105 as shown, o-rings 1121 helping to seal chamber 1100 aswell as providing a low friction surface between the impeller end capsand the chamber end caps.

The sealing members (i.e., seals 1109, 1115, 1119 and 1121) are designedto insure that cavitation chamber 1100 can be either evacuated,preferably to a pressure of less than the vapor pressure of thecavitation fluid, or pressurized, preferably to a pressure of at least1,000 PSI, more preferably to a pressure of at least 10,000 PSI, andstill more preferably to a pressure of at least 100,000 PSI. Thus thesealing members are designed to allow the chamber to be either evacuatedfor degassing or pressurized during operation. It will be appreciatedthat the invention is not limited to a particular seal arrangement andthat there are numerous means for adequately sealing chamber 1100. Theexact nature of a particular seal depends on whether the surfaces to besealed are static, such as end cap 1105 and chamber body 1001, ordynamic, such as drive shaft 809 and end cap 1105. Depending upon theintended cavitation medium as well as the desired pressure ranges, avariety of sealing member types can be used with the inventionincluding, but not limited to, o-rings, static packing seals such asgaskets and dynamic packing seals such as flanges, rings, and adjustablesoft packings.

Preferably chamber 1100 also includes a pair of chamber inlets 1121,thus allowing the chamber to be filled, drained and/or coupled to acavitation fluid circulatory system as described in detail in co-pendingapplication Ser. No. 11/001,720, the disclosure of which is incorporatedherein for any and all purposes.

The embodiment shown in FIGS. 8-11 is only meant to illustrate onepreferred implementation of the invention. It will be appreciated thatthe invention is not limited to a particular impeller design, chambershape, cavitation system, impeller sealing means, impeller drivingmeans, etc. Nor does the invention require that the shape of theimpeller assembly match that of the cavitation chamber. Thus, forexample, a cylindrical impeller can be used with a spherical orrectangular chamber.

FIG. 12 illustrates an impeller 1200 that uses a single cylindricalimpeller blade 1201, impeller 1200 suited for cavitation chambersutilizing acoustic drivers. Cylindrical impeller blade 1201 isfabricated from a cylinder and attached to end caps 805/806 aspreviously described. Preferably impeller blade 1201 includes aplurality of small holes 1203 which allow pressure equalization andfluid flow between the inside and the outside of impeller 1200 (i.e.,within chamber 1000). Preferably holes 1203 are located near the edgesof impeller cylinder 1201, thus minimizing turbulence within the centralregion of the chamber. Although holes 1203 can be bored into one or bothend caps 805/806, typically such a configuration results in greaterturbulence. The major benefit of a cylindrical impeller such as impeller1200 over a multi-bladed impeller such as impeller 800 is that thecylindrical impeller does not create as much turbulence within thecavitation medium since it does not have one or more blade edges whichmust slice through the cavitation medium during rotation.

FIG. 13 is a cross-sectional view of another embodiment of theinvention. This embodiment is similar to that shown in FIGS. 8-11, butthe cylindrical chamber cavity is replaced with a spherical cavity. Inthis embodiment, chamber 1300 is comprised of two pieces 1301/1302 thatare bolted together with a plurality of bolts 1303 to form the chamber.At least one sealing member 1304 (e.g., o-ring, gasket, etc.) sealsportion 1301 to portion 1302. Prior to assembling portions 1301/1302,impeller 1305 is located within the spherical cavity 1307 such thatspindle 1309 is fitted within bearing 1311. Spindle drive shaft 1313 isfitted through a seal/bearing housing 1315 incorporated within chamberportion 1302. Preferably an end cap 1317 is bolted to chamber portion1302, end cap 1317 including an additional sealing member 1319. Aspreviously noted, preferably the chamber includes a pair of chamberinlets (not shown), thus allowing the chamber to be filled, drainedand/or coupled to a cavitation fluid circulatory system. Impeller 1305preferably includes at least 2 blades. As previously noted, if acousticdrivers are used with chamber 1300, impeller 1305 can utilize a solid orbladeless impeller design, thus minimizing impeller induced turbulence.If a bladeless impeller is used, preferably it includes a plurality ofholes near the spindle shaft ends of the impeller, thus allowing fluidto flow between the inside and outside of the impeller.

The present invention is not limited to cavitation chambers that can beassembled around the impeller. For example, FIG. 14 is an illustrationof a spherical cavitation chamber 1400 which is fabricated in such a wayas to preclude disassembly. One technique for fabricating such a chamberis disclosed in co-pending application Ser. No. 10/925,070, filed Aug.23, 2004, entitled Method of Fabricating a Spherical Cavitation Chamber.An impeller assembly 1500 such as that shown in FIGS. 15 and 16 can beinserted through port 1401 and then sealed to chamber exterior surface1403 with a flange 1501 and one or more sealing members 1701 (e.g.,o-rings, gaskets, etc.). In addition to flange 1501, impeller assembly1500 includes an impeller blade 903, a sealing/bearing assembly 1505,and a drive shaft 1507 to be coupled to a drive motor (not shown). FIG.17 is an illustration of impeller assembly 1500 sealed to chamber 1400.

FIG. 18 is a cross-sectional view of a spherical cavitation chamber 1800similar to that shown in FIG. 14, except that the chamber has two portsfor use with two impeller assemblies 1801. The impeller blade 1803 foreach assembly 1801 is short enough to insure that the two blades willnot interfere with one another during operation. In a preferredembodiment, each drive shaft 1805 includes a timing mark so that thelocation of each blade within chamber 1800 can be determined, thusallowing the timing of the two impellers to be synchronized (i.e.,turning at the same rate and within the same plane within the chamber).Chamber 1800 also includes a pair of inlets 1807 for use in filling ordraining the system, or for use with a cavitation fluid circulatorysystem.

As will be understood by those familiar with the art, the presentinvention may be embodied in other specific forms without departing fromthe spirit or essential characteristics thereof. Accordingly, thedisclosures and descriptions herein are intended to be illustrative, butnot limiting, of the scope of the invention which is set forth in thefollowing claims.

1. A method of stabilizing bubbles within a cavitation chamber, themethod comprising the steps of: rotating at least one impeller locatedwithin the cavitation chamber, wherein cavitation fluid within thecavitation chamber rotates in response to said impeller rotating step;and cavitating said bubbles within said cavitation fluid within thecavitation chamber.
 2. The method of claim 1, further comprising thestep of positioning an axis of rotation corresponding to said at leastone impeller within a horizontal plane.
 3. The method of claim 1,wherein said rotating step is stopped prior to performing saidcavitating step.
 4. The method of claim 1, wherein said rotating step isperformed continuously during said cavitating step.
 5. The method ofclaim 1, said rotating step further comprising the steps of: ceasingsaid rotating step; and positioning said impeller into a first positionprior to initiating cavitation within the cavitation chamber.
 6. Themethod of claim 5, further comprising the step of determining said firstposition on the basis of minimizing interference between said impellerand a source of cavitation energy.
 7. The method of claim 1, saidrotating step further comprising the steps of: ceasing said rotatingstep; and locking said impeller into a first position prior toinitiating cavitation within the cavitation chamber.
 8. The method ofclaim 7, further comprising the step of determining said first positionon the basis of minimizing interference between said impeller and asource of cavitation energy.
 9. The method of claim 1, said rotatingstep further comprising the steps of: ceasing said rotating step; andpositioning said impeller into a first position after initiatingcavitation within the cavitation chamber.
 10. The method of claim 9,further comprising the step of determining said first position on thebasis of minimizing interference between said impeller and a source ofcavitation energy.
 11. The method of claim 1, wherein said rotating stepis performed for a period of time prior to performing said cavitatingstep, said period of time sufficient to axially position said bubblesalong an axis of rotation corresponding to said impeller.
 12. The methodof claim 1, wherein said rotating step is performed for a period of timeprior to performing said cavitating step, said period of time sufficientto pull said bubbles away from an inner wall of the cavitation chamber.13. The method of claim 1, wherein said rotating step comprises thesteps of: driving a first impeller with a first motor; driving a secondimpeller with a second motor; and coaxially aligning a first axis ofrotation corresponding to said first impeller with a second axis ofrotation corresponding to said second impeller.
 14. The method of claim13, further comprising the step of synchronizing rotation of said firstimpeller with rotation of said second impeller.
 15. The method of claim1, further comprising the step of degassing said cavitation fluid priorto performing said cavitating step.
 16. The method of claim 15, whereinsaid degassing step degasses air from said cavitation fluid.
 17. Amethod of stabilizing bubbles within a cavitation chamber, the methodcomprising the steps of: locating an impeller within the cavitationchamber; positioning an axis of rotation corresponding to said impellerwithin a substantially horizontal plane; rotating said impeller locatedwithin the cavitation chamber, wherein cavitation fluid within thecavitation chamber rotates in response to said impeller rotating step;and cavitating said bubbles within said cavitation fluid within thecavitation chamber.
 18. The method of claim 17, wherein said rotatingstep is stopped prior to performing said cavitating step.
 19. The methodof claim 17, wherein said rotating step is performed continuously duringsaid cavitating step.
 20. The method of claim 17, further comprising thestep of degassing said cavitation fluid prior to performing saidcavitating step.
 21. The method of claim 20, wherein said degassing stepdegasses air from said cavitation fluid.